Helmholtz, Occhio e triangolo dei colori

1994 - Helmholtz, Eye and Colour Triangle - - 100 Pf. - German pfennig - Copie 19,000,000 - Policromo - Michel DE01752 - Stanley DE02594 - Scott DE01867 - Yvert Tellier DE01583 - 9/8/1994 - comb 14 - 43 x 26 mm - Offset